System for visual display of signal parameters such as the parameters of speech signals for speech training purposes

ABSTRACT

A system for speech training is described which stores and displays speech parameters (pitch, intensity, etc.) on a television screen as a trace or line. Two parameters from the same speech signal (for example, pitch and intensity) are stored and displayed simultaneously, one on the lower half of the screen and one on the upper half of the screen. The same parameters from the voice of a speech therapist can be displayed along with those of a trainee. The therapist&#39;&#39;s and trainee&#39;&#39;s parameters are separated using black traces for the trainee, and white traces for the therapist on a grey background. Both the therapist&#39;&#39;s traces and the trainee&#39;&#39;s traces may be independently moved about the screen so that they can be overlaid for direct comparison, thus assisting trainees, especially the deaf, to improve their speech. The digital system produces a visible trace when the sum of the line count number plus the signal value equals a predetermined value. Trace-broadening indicias are formed by a plurality of sum values.

United States Patent 1 91 1111 81,059

Stewart 1 1 Apr. 29, I975 SYSTEM FOR VISUAL DISPLAY OF SIGNAL PrimaryExaminer-William C. Cooper PARAMETERS SUCH AS THE Assistant E.raminerE.S. Matt Kemeny AR M T S 0F SPEECH SIGNALS FOR Attorney, Agent. or Firm-Martin Lu Kacher SPEECH TRAINING PURPOSES [75] Inventor: Leslie C.Stewart, Rochester, NY. [57] ABSTRACT A system for speech training isdescribed which stores and displays speech parameters (pitch, intensity,etc.) on a television screen as a trace or line. Two paramel l Filediug. 16. I973 ters from the same speech signal (for example, pitch [21 1App No; 388,771 and intensity) are stored and displayed simulta neously,one on the lower half of the screen and one on the upper half of thescreen. The same parameters [73] Assignee: Center for CommunicationsResearch, Inc., Rochester, NY.

[52] US. Cl 179/1 SP f th oi of a s eech therapist can be displayed [5|]Int. Cl. G101 1/14 along ith tho e of a trainee, Tho therapist's andFleld Search 179/l 43/5; 235/ trainees parameters are separated usingblack traces 340/324 AD for the trainee, and white traces for thetherapist on a grey background. Both the therapists traces and thetrainees traces may be independently moved about [56] References Citedthe screen so that they can be overlaid for direct com- UNITED STATESPATENTS parison, thus assisting trainees, especially the deaf. to2.416.353 2/1947 Shipman ct al. 179/1 improve their speech. The digitalsystem produces a 2.416.353 2/1947 Shipman et a1... 179/1 SP visibletrace when the sum of the line count number 2920.31 /196 o on t 43/5plus the signal value equals a predetermined value.

Trace-broadening indicias are formed by a plurality of .9.. 9 9 un ersum values. 3.791483 2/1974 Bushnell 340/324 AD 17 Claims, 8 DrawingFigures pun wq- /I8 [I6 /Z4 TVILINES I0 INPUT neeiaeturm DISPLAY M -53umr uznomes CONTROL '1' w BLK ion .--EoR-w met-1 1 '1 l I 'r-s IIIC sw YI F /22 12!- I wane sw Tmne l I 1-1. F'Osv SW comm i l 1N1 vPosswPARAMETER: 5 T

SELECT sw l DISPLAY mmmmzsaszs SHE] 10F 6 mum L SYSTEM FOR VISUALDISPLAY OF SIGNAL PARAMETERS SUCH AS THE PARAMETERS OF SPEECH SIGNALSFOR SPEECH TRAINING PURPOSES The present invention relates to visualdisplay systerns and particularly to a system for providing a graphicdisplay of signal parameters which remain displayed unless or until suchtime as it is desired to change the display.

The invention is especially suitable for displaying one or more speechparameters for speech training purposes. Features of the invention aregenerally applicable for providing displays of various signal parametersin the form of a graph which represents the parameter as a function oftime (viz., a graphic display in rectangular coordinates) as well as forother visual signal display purposes.

Speech training and therapy depends in large measure upon the skill ofthe therapist and the cooperation of the trainee. The therapist mustinterpret the deficiencies in the various parameters of the traineesspeech, teach the trainee how to correct his speech to accommodate forthe deficient parameters and determine if the trainee has learned thenecessary corrections by listening to his attempts. The speech trainingprocess is therefore necessarily iterative and time consuming. A visualspeech training aid as provided in accordance with the invention can beof significant assistance to the therapist in analyzing the performanceof the trainee and determining the speech parameters in whichdeficiencies exist and in communicating performance targets anddirections to the students. lt provides for storage and display ofspeech parameters and characteristics such as pitch, intensity,nasality, voice, and voiceless speech, etc.

The system includes memories having storage for a portion of a speechparameter such as pitch or intensity and provides a graphic display ofthe parameter as a trace or line on a screen, such as a televisionmonitor screen. In a typical operation the trainee presses a displaybutton while he speaks. When the button is re leased, the last fewseconds of the speech are translated into parameters of speech, saypitch and intensity, and are permanently retained in memory. The signalsin memory are displayed on the screen in a frozen" or permanentlydisplayed manner. A plurality of parameters from the same speech signal(for example, pitch and intensity) can be displayed simultaneously, say,one on the lower half of the screen and one on the upper half of thescreen. The same parameters from the voice of the therapist can bedisplayed along with those of the trainee and may be distinquished bythe trainee display being made up of black traces while the therapistdisplay is in the form of white traces, or vice versa. The systemprovides facilities for independently moving the displays about thescreen so that they can be overlaid for direct comparison.

Accordingly. it is an object of the present invention to provide animproved system for speech training.

It is another object of the present invention to provide an improvedsystem which aids in the training of the deaf and other hearing impairedper ms to speak.

It is still another object of the present invention to provide animproved system for displaying speech which is especially useful as avisual speech training aid.

It is a further object of the present invention to provide an improvedsystem for the storage and display of speech parameters, for examplepitch and intensity.

It is a still further object of the present invention to provide animproved system for speech training and therapy which is easy to use byboth the trainee and the therapist.

It is a still further object of the present invention to provide animproved system for speech training and therapy, whereby a plurality ofparameters of the same speech signal can be displayed simultaneously.

it is a still further object of the present invention to provide animproved speech training system whereby a plurality of different speechparameters can be displayed simultaneously and independently moved onthe display for comparison purposes (viz., display of speech parametersproduced by a trainee and therapist can be overlaid on the screen fordirect comparison).

It is a still further object of the present invention to provide aquantitative display of speech parameters.

It is a still further object of the present invention to provide animproved system for storing parameters, such as pitch and intensity, ofsegments of speech such as phonemes, words, and phrases, and displayingthem for as long as desired until replaced by the display of parametersof other speech segments.

It is a still further object of the present invention to provide animproved system for visually aiding speech training which enables atrainee to visually observe when he is talking too loudly or too softly,with too high or too low a pitch, too much through his nose or too muchthrough his mouth, and how well he makes speech sounds.

It is a still further object of the present invention to provide animproved system for visually aiding speech training whereby traces ofspeech parameters derived from the therapist's voice can be continuouslydisplayed on a screen while traces of like speech parameters derivedfrom the trainees voice are successively displayed as the traineepractices emulation of the therapists voice, the display thus providinga quantitative measure of the degree of learning achieved by thetrainee.

Aspects of the invention are also generally applicable for providinggraphic displays of functions, such as analog signals which vary withtime.

It is thus a further object of the invention to provide an improvedsystem for providing graphic displays of analog signals on parameters ofsuch signals as in rectangular coordinates.

lt is a still further object of the invention to provide an improvedsystem for graphic display of signals in rectangular coordinates whereinthe display can be controlled so as to modify the trace representing thesignal in selected portions of the trace.

it is a still further object of the present invention to provide animproved system of generating visual displays wherein the display iscontrollable to change the trace which depicts the signal as by causinga portion of the trace to disappear, become broadened or to be marked.

It is a still further object of the present invention to provide animproved display system wherein a trace of a signal to be displayed isobtained by digitally controlling the intensity of a writiing orscanning beam.

Briefly described, a system for providing a graphic display inaccordance with the invention includes a recirculating memory havingstorage for signals, for ex ample, digital characters, representingsuccessive val ues of the signal to be displayed. Display means such asa television monitor are provided which display signals as visibletraces on the plurality of lines which are disposed one alongside theother in succession. The display is generated by reading out thememories concur rently with each of the lines. Display control means areresponsive to the value to which each signal read out of the memorycorresponds and the position of the line with respect to the other lineson the display. When the signal value and the line position numbercombine (sum) to provide a value equal to the predetermined value orvalues (as for trace broadening to provide indicia in selected portionsof the trace), the trace is controlled to become visible as by beingdarkened or lightened (to provide a black or white trace). The sequenceof visible traces constitutes a line or trace which represents thesignal. Since the signals in memory recirculate, the display remains onthe screen in a fro zen" or continuous manner until it is replaced witha new signal portion. Means are provided for incrementing ordecrementing the combined value of signal and line position so as tochange the position of the line or trace constituting the displayvertically or horizontally, or to mark the display in a manner toindicate certain signal characteristics or features. Trace-broadeningindicias are formed by a plurality of sum values.

The foregoing and other objects and advantages of the present inventionas well as additional features thereof will become apparent from areading of the fol lowing description in connection with theaccompanying drawings in which:

FIG. I is a block diagram illustrating a display system embodying theinvention;

FIG. 2 is a block diagram showing the input unit of the display systemillustrated in FIG. 1;

FIG. 3 is a block diagram showing the timing unit of the display systemshown in FIG. 1;

FIG. 4 is a block diagram illustrating the control unit of the systemshown in FIG. 1;

FIG. 5 is a block diagram illustrating the recirculating memories of thesystem shown in FIG. 1;

FIG. 6 is a block diagram illustrating the display control unit of thesystem shown in FIG. 1',

FIG. 7 is a waveform diagram illustrating the timing relationship ofpulses produced in the timing unit shown in FIG. 3; and

FIG. 8 is a waveform diagram similar to the diagram shown in FIG. 7, buton an expanded scale.

FIG. 1 illustrates a visual speech training system wherein the inventionis embodied. Two microphones are provided. The T-MIC I0 is provided forthe therapist. Parameters of the therapist's speech result in whitetraces (W) on the display 12. The display 12 used in this embodiment ofthe invention is a conventional television monitor having intensitycontrol or Z axis, vertical sync V and horizontal sync H inputs. Thetrainee or student is provided with a microphone l4 and the parametersof speech, pitch and intensity in the case of this embodiment of theinvention, which the student or trainee speaks into his microphone ll(S-MIC) are displayed as black traces on the screen of the display 12.The pitch parameters maybe displayed in the upper half of the screenwhile the intensity parameters are displayed in the lower half of thescreen. The student's traces are black (BLK) while the therapist'straces are white (W). Their location on the screen identifies theparameter and the color of the trace represents whether it is thestudents or the therapist's speech which is generating the parameter.

Considering the display 12, it will be observed that the display is inrectangular coordinates with the ordinate or Y axis being the televisionline at the horizontal sync lines in the raster scanned on the screen ofthe monitor and the abscissa or X axis calibrated in terms of memoryposition. TV lines 16 through 240 contain the display, while memoryposition 1 to 240 are pro vided for each TV line. Of course the displayis not calibrated in terms of TV lines and memory positions asindicated. The calibration is provided herein solely for purposes ofexplaining the operation of the system. The memory positions in thedisplay correspond to the stages in the re-circulating memories 16 ofthe system. A re-circulating memory of the same length (240 stages inshift registers constituting the memory) is provided for each parameterproduced by the student and the therapist, there being four suchre-circulating memories, one for the intensity parameter of thetherapist; one for the intensity parameter of the student, one for thepitch parameter of the therapist; and one for the pitch parameter of thestudent. The memories also con tain two control memories which, like there circulating memories for the parameter values, store control signalsrepresenting characteristics of the therapists and students speech andcontrol signals. There are two control memories, one for the therapistand one for the student.

The input unit 18 translates the speech signals produced by themicrophones l0 and 14 into digital signals representing successivevalues of parameters and of the speech characteristics and inputs theminto the parameter and control memories in the re-circulating memories16.

The control unit 20 is operated by various switches. The T-S MIC switchis operative to control the selection of either the therapist microphone10 or the student microphone 14, such that either the therapistmicrophone output or the student microphone output will be connected inthe input unit 18 for parameter and control characteristics processing.There are two write switches, one for the therapist and the other forthe student. When the therapists write switch is depressed theparameters and control characteristics of the therapists speech whichare at the time spoken into the microphone 10 are stored in the memory16 and used to update the display 12. only the therapists white traceswill be updated, and the students traces, the black traces, remainfrozen on the screen. When the student's write switch is depressed,signals from the student microphone 14 will be translated intoparameters and control signals, which will be stored in the memory 16and used to update the black traces constituting the student display.The horizontal position of either the student or the therapist tracescan be controlled (viz., the traces can be moved horizontally from rightto left across the screen by operating the horizontal positionswitches). Similarly, the vertical position switches will control thelocation of the student or therapist traces causing them to move up anddown on the screen. The parameter selection switch is provided when itis desired to input another parameter, say nasality, as obtained from anaccelerometer mounted on the student's nose, into the input unit 18.

The timing unit 22 generates all of the timing signals such that data isinputted once each 128 horizontal lines into the memories for purposesof updating the memories. The timing unit also controls the shifting orre-circulating of the data through and around the memory registers. Thetiming unit 22 further provides line count signals to the displaycontrol unit 24. The line count corresponds to the number of thehorizontal line which is being scanned on the display monitor 12. Thetiming is such that the memories are read out in their entirety duringeach horizontal scan (viz., the memory re-circulates in less time thanit takes the beam to scan a horizontal line). it will be noted thathorizontal and vertical sync is provided by the timing unit to thehorizontal and vertical sync inputs of the display so as to insureproper synchronism and coherency of read-out from the memories with thescanning of the horizontal lines and retrace of the entire raster (whichoccurs upon occurrence of the vertical sync pulse). The value of thedigital signals read out of the memory and the line count value takentogether determine whether a spot or portion of a trace should bedisplayed or written on a particular horizontal line. The sum of theline count and digital value is determinative. For example, the firstline which is used in the display is horizontal line No. 16. If theparameter represents a large value it should be written at the top ofthe trace or on horizontal line 16. A digital number corresponding tothe sum of the value of the digital signal and the line count isindicative of whether or not the signal is of high enough intensity tobe written on the top line 16. Accordingly, when the sum of the linecount and digital values equals a predetermined number or predeterminednumbers, the display control 24 will be operated to cause the intensityof the beam to be increased in the case of the therapist (light) traces,or decreased in the case of the student (black) traces. As eachhorizontal line is scanned the intensity of the writing beam will beincreased or decreased depending upon whether or not the value of thedigital signals are sufficiently high to equal the predetermined orwriting threshold. Inasmuch as the memory is read out in synchronismwith the horizontal tracing of each line, successive portions of theline will have a spot written thereon. The synchronism of the memoryreadout with the line scanning thus provides for the generation of thetraces constituting the display. In the illustrated display where 224 TVlines are used, and there are 240 stages in the memories, there is apossibility of 53,760 points which can be written. In this particularembodiment of the invention, it will be observed as the descriptionproceeds that each parameter has a memory of 240 words or stages ofseven bits each. Accordingly, only 6,720 bits in total of memory arerequired to provide a display with high resolution, thus affording aconsiderable memory savings.

It will be observed that there are two displays, one on the upper halfand one on the lower half of the screen. These two displays are obtainedby controlling four memories through the timing pulses provided by thetiming unit 22. Two memories, one for the therapist and one for thestudent, provide the pitch parameter display during TV lines to 126. Twoother memories, one for the therapist and one for the student providethe intensity parameter display during the TV lines 128 to 239.

The translation of the speech signals into digital signals may beaccomplished by the input unit which is illustrated in detail in FIG. 2.

Referring to FIG. 2, the inputs T-MlC and S-MlC from the therapist andstudent microphones are selected by a switch 26 which may be relayoperated from the control unit 20. The inputs from the switch areapplied to a pitch analyzer 28 and intensity analyzer 30, a silencecharacteristic detector 32, and an unvoiced speech characteristicdetector 33. The pitch analyzer 28 is a circuit of conventional designwhich follows the fundamental frequency or pitch of the voice. Inessence it is a frequency discriminator which provides a slowly varyinganalog DC voltage-reference may be had to Remaking Speech," by HomerDudley, J. Acoust. Soc. Am., Vol-ll, No. 2 pl69-l77 Oct. i939, for asuitable pitch analyzer.

The intensity analyzer 30 is a broadband amplifier which follows thepeak or average amplitude of the voice signal from the microphone andmay include automatic volume control circuits, sometimes calledcompression circuits, if desired.

The silence detector 32 is an amplifier 36, the output of which isapplied to a Schmitt trigger or other suitable threshold circuit 38. Aperiod of silence, i.e., when the input signal to the amplifier 36 fallsbelow a threshold which may be controlled by varying the referencevoltage to the Schmitt trigger input, allows the Schmitt trig ger outputvoltage to drop to a low output voltage state. An inverter 40 changesthe logic level such that a period of silence is represented by a highlogic level.

The unvoice detector 33 includes a detector circuit 42 which may containa high pass and a low pass filter. The ration of the high pass to lowpass filter outputs is obtained, as in a potentiometer and produces anoutput voltage which operates the Schmitt trigger circuit 44 when thehigh pass filter output is greater than the low pass filter output.Since a voice signal containing larger energy in the high frequencycomponents thereof represents an unvoice condition, the Schmitt triggeroutput voltage will be at a high level when the speech signal has anunvoice characteristic. As the discussion proceeds, it will be observedthat a high voltage level is taken to represent a logical 1" and a lowvoltage level a logical Another parameter may be provided by an accelerometer 46 which may be placed on the students nose region. The output ofthe accelerometer is amplified in an amplifier 48 and may be applied toa switch 50. The switch 50 is operable by the parameter selection buttonof the control unit 20 when it is desired to display a speech parameterknown as nasality.

A pair of analog digital converters A/D-l, and AID-2, 52 and 54,translate the analog signal which is applied to the input thereof into aseven-bit digital word. The converter 52 provides a digital wordindicated as DW-l consisting of the bits D-l-O through D-l-6. The otherconverter 54 provides a digital word DW-2 consisting of seven bits D-2-0to D-2-6. Conversion of succes sively occurring signals representing thepitch and intensity parameters is provided by operating the samplingcircuits of the converters upon occurrence of a convert pulse, CP,produced by the timing unit 22. Upon each C? pulse a sample of theanalog voltage presented from the analyzers 28 and 32 to the input ofthe converters 52 and 54 is converted into the digital word DW-l andDW-2. For purposes of simplification of the description of the system.only the pitch and intensity parameters is mentioned herein. It will beappreciated, of course, that other parameters such as the nasalityparameter may be displayed.

The timing unit is illustrated in FIG. 3. Reference may also be had toFIG. 7 and 8 which illustrate the waveforms of the timing pulses. A15.36 Kl-lz freerunning clock oscillator 56 controls a us, one shotmultivibrator 58 which produces the horizontal sync pulse waveformH-SYNC. The pulses from the clock oscillator 56 are divided in frequencyby an eighbstage binary counter 60. The counter thus divides by 256which corresponds to the number of TV lines (horizontal lines) in theraster on the display screen 12(FlG. l). Decoders 62 which may beprovided by AND gates connected to different stages of the counter 60derives a pulse of the duration during which counts 247 to 255 areproduced (i.e., during the occurrence of TV lines Nos. 247 to 255). Thispulse is used as the vertical sync pulse V-SYNC, and may be applied tothe vertical sync pulse input of the display 12 (FIG. 1). An OR gate 64combines the horizontal and vertical sync pulse to produce the compositesync waveform C-SYNC, which is also shown in FIG. 7. The decoders 62provide pulses at counts and 128 which are combined in an OR gate 66 toproduce the start vertical clock pulse signal also illustrated in FIG.7. The I28 pulse counted by the counter produces a square wave having afrequency of 120 Hz. The lowest counter stage produces a 60 cycle squarewave pulse train. The 120 Hz counter output drives a 5 [.LS one-shot 68to produce the sample pulse. The sample pulse controls the timing ofwriting of successive digital words in the memories, as will beexplained more fully hereinafter. The trailing edge of the samplingpulse drives another 5 p.s one-shot 70 which produces the convert pulseCP. The convert pulse when produced allows the analog to digitalconverter 52 and 54 to sample a successively occurring speech parametersignal from the pitch and intensity analyzers 28 and 30.

Another free-running clock oscillator CLK-OSC-2, 72, produces clockpulses at a 4.2 MHz rate. The rate is selected so that greater than 240horizontal clock pulses, HC, will be produced during each horizontalsync pulse interval. It is these 240 pulses which will enable all of thestages of the memories to be read out during the scan of each horizontalline. The trailing edge of the horizontal sync pulse sets a flip-flop 74which enables the clock oscillator 72 and starts the horizontal clock.The horizontal clock pulses are counted by an eight-stage binary counter76. An AND gate decoder 78 connected to different stages of the counter76 decodes the 240th horizontal clock pulse and resets the flip-flop 74thus stopping the clock oscillator 72. As shown in FIG. 8 in thewaveform for the memory clock, MC, the reset occurs before the onset ofthe next horizontal sync pulse.

The start vertical clock pulse sets a flip-flop 80 which enables an ANDgate 82 through which horizontal sync pulses are applied to the input ofa seven-stage or divideby- I 28 binary counter 84. The leading edge ofthe horizontal sync pulse causes the counter 84 to change state. Whenthe last stage of the counter returns to 0," the negative going edgedrives a l as one-shot 86 through an inverter 88. This presets thecounter 84 to a count of 16. The one-shot 86 output pulse also resetsthe flip-flop 80. The counter 84 will therefore initially be preset to acount of 16. The output of the counter 84 is the vertical word. It is aseven-bit binary number, the decimal equivalent of which corresponds tothe TV line which is being scanned on the screen of the display l2. Thefirst visible line corresponds to TV line 15 (i.e., the vertical word ismade up of seven binary 0 bits). Line 16 will be a binary word having abinary I bit in the 2 position. line 17 will correspond to a verticalword with a binary I in the 2 and in the 2 positions, and all the restof the bits binary Os. The vertical word will have all ls at line 128.

As mentioned previously, the screen is divided into two halves, thedividing point being at the l28th line. Each parameter will be displayedon 112 visible TV lines, thus it is suffeicient that the vertical wordcorresponds to a decimal maximum of I28. Selection of the upper andlower halves of the display is obtained by means of the top/bottom, orTB, signal, which is the 60 Hz waveform from the counter 60. Duringone-half of that waveform, the upper I28 TV lines are used, and duringthe other half the bottom I28 TV lines are used. The vertical words aretranslated into line-count words LC-l and LC-2. Adders 90 and 92 areused for vertical position control purposes for incrementing ordecrementing the LC-l and LC-2 words, respectively when the LC-I word isincremented or decremented, the display in the upper half of the screenis moved vertically, while when the LC-2 word is incremented ordecremented, display in the lower half of the screen is moved.

The line count words are incremented by vertical positioning words VPW-Iand VFW-2, which are respectively added to the vertical words in adder90 and adder 92, to produce the line count 1 and line count 2 words. Anup/down counter 94 in the control unit 20 (see also FIG. 4) produces theVPW-l word while another up/- down binary counter 96 produces the VPW-2word. In the control unit there are provided a pair of switches formoving the display in the upper half of the screen up or down. These areshown as the VPOS-UP-I switch and the VPOS-DN-l switch. Similar switchesVPOS- UP-2 and VPOS-DN-Z control the counter 96 for mov ing the displayin the lower half of the screen up or down. These switches control thecounting direction either up or down in the counters 94 and 96. Thecounters receive the 60 Hz TB wavform. The stages of the counter 94provide the VPW-l word and the eight stages of the counter 96 providethe VFW-2 word. The highest order or 2 bit of these words is used as asign bit.

When the up switches are closed for example, the counter outputsincrease at the 60 Hz rate. When the up switch is opened the countershold their current count. The adders 90 and 92 add these verticalpositioning words to the vertical word from the counter 84. The lowerorder 7 sum bits become the line count words LC-l and LC-Z. Of coursewhen the counter 94 and 96 outputs are all 0's, the vertical wordsbecome the LG! and LC-2 words. For positive displacements the adders 90and 92 perform a normal binary addition. When negative displacementoccurs, which will be indicated by the sign bit in the VPW-l and VFW-2words, the sign bit is used to convert the operation in the adder totwo's complement addition, so as to subtract the vertical positioningwords from the vertical words. There is therefore, facility for positiveand negative displacements corresponding to l l l and I28 TV linesrespectively. This is enough to move the trace on the screen completelyoff the screen in either direction. If the displacement is greater thanthe aforementioned 111 or I28 lines, the 2 sum bit from the adder 90 andthe 2 sum bit from the adder 92 becomes a binary l This bit is invertedand used to provide the OB-l and 08-2 bits for offset blanking purposes.The OB-l bit will prevent traces in the upper half of the display belowthe I28 TV line, or above the 16 TV line, while the OB-Z bit willprevent tracing below the 240th TV line or above the I28 TV line.

Referring again to FIG. 4, there are provided controls for horizontalpositioning and writing. These controls are operated by the horizontalposition switch HPOSSW-l and WSW-l which control horizontal positioningand writing or updating of the display in the upper half of the screen.Two similar swithes HPOSSW-Z and WSW-2 control horizontal positioningand writing in the lower half of the screen. When the horizontalpositioning switch HPOSSW-l is depressed a flip-flop 98 is set. Thisenables an AND gate 100 to pass a shift pulse through an OR gate 102 andanother OR gate 104 to the memory clock MC-1 output of the control unit.The memory clock output provides pulses for shifting or advancing thememories. Since a shift or advance of data aroung the memory (viz., fromone stage to the next) causes a horizontal displacement of the trace inthe display 12, the traces will be horizontally shifted when thehorizontal position switch is operated. Horizontal positioning by virtueof the generation of the shift pulse occurs only during the samplingpulse (SP) interval, (see the waveform for the memory clock in FIG. 8).The shift pulse is generated when the sampling pulse sp passes throughan AND gate [06. The sampling pulse also passes through an OR gate 108.The leading edge of sampling pulse triggers a 1 ps, one-shot 110. Afterthe l as interval of the pulse from the one-shot 110, another 1 ,usone-shot 112 is triggered. The pulse from the one-shot 112 constitutesthe shift pulse which passes through the AND gate 100, OR gate 103, ORgate 104 to shift data in the memory which controls the upper half ofthe display. The next sample pulse resets the flip-flop 98.

The data in the memory may, if desired, be moved only one memory cell ata time. To obtain such operation, the horizontal position switchHPOSSW-l, for instance, must be closed for less than one-half second.The flip-flop 98 is then set, as was the case for horizontal positioningdescribed above. The output of the flipflop 98 is transmitted via an ORgate 114 to set a flipflop 116. When the flip-flop 116 is set, aone-half second one-shot H8 is triggered. During the one-half secondduration of the one-shot 118 pulse, the AND gate 106 is inhibited via aninverter 120 from passing the sample pulse, SP. Instead, another ANDgate 122 is enabled by the flip-flop 116 in its set condition. The ANDgate 122 then passes the SP pulse which triggers the one-shot 110 andthe one-shot 112. The shift pulse is then generated and resets theflip-flop I16 so that no more shift pulses occur if the horizontalposiion switch HPOSSW-l has been released. If this switch is closed morethan a half second, then the single shift pulse is generated. After onehalf second the one-shot 118 pulse is no longer produced and theinverter 120 enables the AND gate 106 which allows the train of samplepuls t pass through the AND gate 106 for generating a series of shiftpulses each during a successive sample pulse period.

When writing is desired, the write switch. say WSW- l, is depressed. Aflip-flop 124 is then set. The output of the flip-flop enables an ANDgate 126 via an OR gate 128. The AND gate 126 passes the sample pulses,SP, to provide the enable write, ER-l, pulses for the memories whichcontrol the display in the upper half of the screen. in other words,when the ER-l waveforem is high, the output of the analog to digitalconverters 52 and 54 (FIG. 2) are connected to the memory inputs. Thecontrol memories are also enabled to receive the silence and unvoicebits from the input unit.

The flip-flop 124 when set by operation of WSW-l also enables an ANDgate 130. The AND gate 130 passes the shift pulse to the MC-] output.Since the shift pulse occurs during the horizontal retrace inter valsand are coincident with the ER pulses (see FIG. 8), the data is shiftedinto the memories during the horizontal retrace intervals. Since thesample pulse SP occurs every 128 horizontal sync pulses, a new data wordor control word is shifted into the memories every 128 horizontal syncpulses. Between entries of new data or control words the memoriesrecirculate 127 times.

When the write switch is released the next sample pulse followingrelease resets the flip-flop 124. When the flip-flop is reset thenegative going edge of its output pulse triggers a 20 ms one-shot 132and provides the end of writing pulse EWl to denote the end of writingon the upper half of the screen. The pulse from the one shot 132 alsoenables the gates 126 and 130 which allows additional ER-l and shiftpulses to be applied to the memories. Thus, writing continues during the20 ms EW-l pulse. The analog-to-digital converters 52 and 54 (FIG. 2)are reset on the leading edge of the CP pulse which follows the samplepulse. Thus a new conversion is started on the trailing edge of the CPpulse which is complete before the next sample pulse.

The horizontal positioning and writing on the lower half of the screenis controlled by the HPOSSW-Z and the WSW-2 switches. These switchesoperate a write and horizontal position control logic 134 identical tothe logic associated with HPOSSW-l and WSW-l switches. The logic 134produces the ER-2, MC-2 and EW-2 pulses which control the memoriesassociated with the lower half of the screen of the display 12 (FIG. 1).

In the event that shift pulses are not applied to the memory clock MCIand MC-2 outputs, the horizontal clock l-lC are applied to these outputsvia the OR gate 104 and an OR gate 136.

The recirculating memories are shown in FIG. 5. There are two memoriesand 142 for data word DW-l. Two memories 144 and 146 for DW-Z and twocontrol memories 148 and 150. The enable recirculating pulse ER-l mustbe present for writing to occur in the data memories 140 and 144, and inthe control memory 148. Since the ER-l pulse will be produced only whenthe write switch WS-l used by the therapist is operated. only data andcontrol words due to the therapist's speech will be written intomemories 140, 144 and 148. Similarly, only operation of the write switchWS-2 used by the student or trainee will produce an ER-2 pulse. Datawords representing parameters due to the student's speech will bewritten in data memories 142 and 146 and in control memory 150.

The data memory 140 is typical of all of the data memories. It containsmemory logic 152 for the first data bit D-l-O of DW-l; memory logic 154which is similar to the logic 152 for the second data bit D-l-l of DW-l,and additional memory logics for each of the remaining bits D-l-2 to D-l-6 of DW-l. Only the logic 152 for the first bit D-l-l is shown tosimplify the illustration. The control memories have memory logic fortwo bits indicated as C-l-l and Cl2 for the control memory 148, and C2land C-22 for the control memory 150. Since the memory logic 152 istypical, it alone will be described in detail.

A shift register 158 which may be a dynamic MOS register, has a lengthor capacity for 240 bits of data. In the absence of a writing orhorizontal positioning op eration. the ER-] pulse is low and an AND gate160 is enabled, via an inverter 162. The HC pulses are applied on theMC-l line to the shift input of the register 158. Each of the 240 MCpulses due to the horizontal clock cause the bits in the register 158 toshift one position for each HC pulse and thus the entire register isread out during each horizontal line time. In other words, during thetime a TV line is scanned on the screen of the display, each bit in theregister 158 shifts succes sively to all positions and is recirculatedvia the AND gate 160 and an OR gate 162. The bits may be read out at theoutput of the OR gate as they recirculate. The bits read out of thisfirst memory logic 152 are indicated as being the RD-l-O bits of theRDW-1A word. It is the RD-W-lA word which controls the display to writethe therapists trace representing the pitch parameter in the upper halfof the display. When a new data word is to be entered in memory the ER'Ioutput goes high. thus enabling a gate 164. The gate 164 passes the Dl0bit of the DW] word which is entered into the shift register by theshift pulse which is produced and appears on the MC-l input line to theregister 158.

Memories 144 and control memory 148 share the MC-l clock and produce theRDW-2A data word and the control word consisting of the RC-l-l and RC--1-2 bits. The data memories 142 and 146 and the control memory 150share the M02 clock and produce the data word RDW-1B and RDW-ZB. Thecontrol memory 150 produces the control word consisting of the bitsRC-Z-l and RC-2-2.

The control memories receive the control word EW. SlL and UNV bits. TheEW-l bit is applied to the first control memory 148 and the EW-Z bit tothe other control memory 150. A control word generator 166 and anothercontrol word generator 168 respectively associated with the controlmemory 148 and the control memory 150 translate the three controlcharacteristic signals into the two-bit control words which are storedin the control memories. The logic of the control word generatorconsists of inverters and gates as shown in the case of the generator166 which provide the following logical operations. When EW is high Clis a l and C2 is a 1. When SlL is high Cl is a l and C2 is a 0. When UNVis high Cl is a O and C2 is a l. When EW, SlL and UNV are all low C1 isO and C2 is also 0.

The control words read out of the memories 148 and 150 are reconvertedinto control bits by recorded control word regenerating logic 170 and172. The logic 170 is typical. It produces and end of writing EOR-Alevel. a SlL-A level. and a UNV-A level, depending upon the controlcharacteristics of the therapist's speech. The work regenerator logic170 consists of in verters and AND gates which provide the inverse ordecoding operation of the operation provided by the control wordgenerators 166 and 168. The other control word regenerator 172 which isassociated with the memory 150 which stores the student's speechcharacteristics produces the EOR-B. SlL-B, and UNV-B levels which dependupon the student voice characteristics.

The display control unit 24, shown in detail in FIG. 6 converts thebinary data stored in the recirculating memories into a TV raster formatin which the parameter stored in memory becomes a trace on the screen.Consider the formation of the trace corresponding to the data stored inmemory 140, the words RDW-lA each consisting of seven bits are read out240 times during each horizontal line scan period. Each data word isadded to the LC-l line count word in a binary adder 174. This binaryadder 174 and OR gate 176 and an AND gate 178 provides control of theformat of the trace representing the pitch parameter in the upper halfof the screen. Accordingly, it is called the trace l-A-UP control. Onlythe 2 2 2, 2 and 2 sum bits from the binary adder 174 are used. The ORgate 176 passes the 2 sum bit when UNV-A is low. When UNV-A is high, theinput to the AND gate 178 from the OR gate 176 is always enabled. Theoffset blanking OB-l level and the SlL-A level are also applied to theAND gate 178. When SlL-A and OB-l are high, the AND gate 178 operates asa decoder of binary values corresponding to decimal 124, 125, 126 or 127(the five most significant sum bits from the adder 174).

Consider, for example. that LG] is a binary number corresponding todecimal 16. which is the line at the top of the screen (see FIG. 1). Asmemory recirculates, if any of the RDW-lA words has a decimal value 108,109, 110, or 111, then these RDW-lA words when added to 16 enable theAND gate 178 for the duration of the data word. The AND gate 178 outputis operative to produce a white dot on the screen at the point of timethat the data word of sufficient value (i.e., 108 or greater) is readout of the memory 140. In this way a trace consisting of dots dependingupon the value of the RDW-1A words stored in the memory 140 will bewritten and displayed on the screen. At mid screen LC-1 is equal todecimal 127. Then a RDW-lA word having a value of 0 will be decoded bythe gate 178. Note that if gate 178 were connected to all of the sevensum bits available from the adder 174, then only a single sum value of127 would be operative to produce the writing of a point on the screen.By using only the five most significant bits. a broader trace coveringfour TV lines is written on the screen. lndicia are the wider traceportions.

1n the event that the UNV-A signal is high. the 2 input to the AND gate178 will always be high. Thus. the OR gate 176 is operative to broadenthe trace to eight TV lines when the UNV-A waveform is high. The displaycontrol also utilizes similar logic including a binary adder. an OR gateand an AND gate connected as shown for the trace lA-UP control for thecontrol of trace 2Adown. trace 1B up. and trace ZB-down associated withthe data memories 142, 144, 146, respectively. The output of the tracecontrols is translated into a video control signal, by video controllogic 180. The video control logic also utilizes the EOR-A and EOR-B andthe TB wavefonn. and determines whether the top or bottom of the screenis to be used. The video control encodes the signals on a three-levelgrey scale, white for the therapist traces, black for student traces,and grey for no trace. It combines the video signal with the C-synccomposite sync signal and applies that the signal to the intensity or Zinput of the video monitor which produces the display on a screen.

Four OR gates 182, 184, 186 and 188 receive the trace control and EORsignals. The upper and lower half of the screen are selected by the ANDgates 190, I92, 194 and 196. When the TB waveform is high, the top halfof the screen is selected by the gates 190 and 194. High level pulses atthe output of an OR gate 198 become white spots on the screen, whilehigh level pulses at the output of another OR gate 200 become blackspots on the screen. An AND gate 202 in conjunction with an inverter 204acts to inhibit black pulses from appearing in the presence of whitepulses. The white spots get precedence. The supply voltage V,- isslightly more positive than the high logic level voltage. The resistor206 and the potentiometers 208 and 210 establish the voltages for thewhite, grey, and black levels of the composite video signal. When whiteis produced, the output of the OR gate 198 and an inverter 212 are high;there is then very little voltage drop across the resistor 206 toprovide the white signal which is amplified by the video amplifier 214.For grey level, the OR gate 198 output is low, while the output of theinverter 212 is high; current is then drawn through the resistors 206and 208 causing a voltage drop at the input to the video amplifier 214.The black level is established when both the gate 198 and the inverter212 outputs are low; then the potentiometers 208 and 210 are bothallowed to draw current through the resistor 206, thus dropping thevideo signal amplitude to black level. The adjustment provided by thepotentiometers 208 and 210 allow for the adjustment of the grey andblack levels.

The composite C-sync signal is added to the video signal after inversionin an inverter 216 and after passing through an isolation diode 218.Accordingly, a succession of white and black dots is written on thescreen of the video monitor to provide the traces representing thesignal parameter.

From the foregoing description it will be apparent that there has beenprovided an improved visual display system which is especially suitablefor use as a speech training system. Variations and modifications in theherein described system, within the scope of the invention, willundoubtedly suggest themselves to those skilled in the art. Accordingly,the foregoing description should be taken merely as illustrative and notin any limiting sense.

What is claimed is:

1. A system for providing a graphic display of a parameter whichcomprises:

a. means having storage for signals corresponding to successive valuesof said parameter,

b. display means for displaying signals as visible traces on a pluralityof lines, one alongside the other in succession, each of said lineshaving a value corresponding to its position with respect to the otherof said lines,

c. means for reading out of said storage means all of said signalsconcurrently with each of said lines, and

d. display control means responsive to the sum of the value to whicheach said signal read out of said storage means corresponds and thevalue corresponding to the position of each line with respect to theother of said lines on said display means for operating said displaymeans to provide a visible trace during readout of each said signal whensaid sum equals a certain value whereby to provide a sequence of visibletraces on said display means which provides said graphic display whichrepresents said parameter.

2. The invention as set forth in claim 1 wherein said display meanscomprises means providing a TV display wherein each of said lines is asuccesive horizontal line of said display, and means for controlling theintensity of said lines to provide said traces.

3. The invention as set forth in claim 2 wherein said storage meanscomprises a recirculating, plural stage digital memory, and said readoutmeans comprises means for reading out digital signals presented in astage in said memory, each during a successive portion of each of saidhorizontal lines.

4. The invention as set forth in claim 3 wherein said display controlmeans comprises means for generating digital controls signalsconcurrently with the generation of each of said horizontal lines, eachof which digital control signals represents the relative position of thehorizontal line for which it is concurrently generated, and means forproviding a signal to said intensity control means for rendering saidline visible when the sum of the values represented by said digitalcontrol signal and said digital signal exceeds a certain value.

5. The invention as set forth in claim 4 including means for changingthe location of said digital signals in said stages of saidrecirculating digital memory for horizontally moving the position ofsaid graphic display of said parameter.

6. The invention as set forth in claim 4 including means for changingthe values of said digital control signals for vertically moving theposition of said graphic display of said parameter.

7. The invention as set forth in claim 4 which comprises a controlrecirculating plural stage digital memory for storing control digitalsignals in successive stages thereof, means for successively reading outdigital signals from said control memory in synchronism with the digitalsignals from said first named memory, and means for controlling saidmeans for providing said signal to said intensity control means inaccordance with the value of said read-out control digital signals.

8. The invention as set forth in claim 4 wherein a plurality of saidrecirculating memories are provided each having storage for a differentparameter, and wherein means are included in said intensity controlmeans responsive to digital signals from difierent ones of said memoriesfor providing the graphic displays which represents different parametersvertically offset from each other.

9. The invention as set forth in claim 4 wherein a plurality of saidrecirculating memories are provided, and wherein means are included insaid intensity control means separately responsive to digital signalsfrom dif ferent ones of said memories for providing said visible traceswith different intensity whereby to simultaneously provide a pluralityof said graphic displays each consisting of traces having a certaindistinct intensity.

10. The invention as set forth in claim 4 further comprising an analogto digital converter for providing said digital signals for storage insaid memory, and means operative once during each repetitive display ofsaid parameter for reading a digital signal from said converter intosaid memory.

11. A speech training system which comprises a. means for providingsignals representing a parameter of voiced speech,

b. recirculating memory means for storing said signals which are voicedduring a period of time,

c. display means for providing a trace representing the signals storedin said memory,

d. timing means for circulating said signals in said memory in timedrelationship with the read out of signals into said display means, and

e. control means operated by said timing means for controlling saidmemory means and said signals which are read out of said memory meansfor varying the location of said trace.

12. The invention as set forth in claim It further comprising aplurality of said memories, a plurality of said means for providing saidsignals at least one from the voice of a trainee and another from thevoice of a therapist, means for storing said trainee signals and saidtherapist signals in different ones of said memories, and means foroperating said display means for providing a plurality of said traces ofeach of the signals from a different one of said memories.

13. The invention as set forth in claim 12, including display controlmeans for moving said plurality of traces with respect to each other sothat they can be overlaid for comparison purposes.

14. The invention as set forth in claim 12 wherein said signalsproviding means includes means for providing a plurality of signals fromthe voice of said trainee and a plurality of signals from the voice ofsaid therapist each representing a plurality of speech parameters,

means for storing each of said signals in a separate one of saidplurality of memories, and means included in said display operatingmeans for providing a plurality of separate traces each corresponding tothe signals stored in a different one of said memories.

15. The invention as set forth in claim 14 further comprising meansresponsive to each of said speech signals for providing signalsrepresenting the certain characteristics of said speech, a recirculationcontrol memory for storing said signals, and means included in saiddisplay control means responsive to said signals stored in said controlmemory for changing the size of said traces representing saidcharacteristics.

16. The invention as set forth in claim 11 wherein said display meanscomprises a screen means for scanning a raster of successive, verticallydisplaced horizontal lines across said screen and means for controllingthe intensity of said lines, said recirculating memory comprisesregister means for storing digital signals corresponding to successivevalues of said parameter, means for providing digital signalscorresponding to the vertical position of each of said horizontal lines,means for reading out said memory during the scanning of each of saidhorizontal lines and means for operating said intensity control means toprovide a trace on said screen when the sum of said vertical positionsignal and said parameter value signal exceeds a predetermined value.

17. The invention as set forth in claim 16 including control means forchanging said trace including means operative to generate digitalcontrol signals, and means for combining said digital control signalsand said sum operative to change said sum.

1. A system for providing a graphic display of a parameter whichcomprises: a. means having storage for signals corresponding tosuccessive values of said parameter, b. display means for displayingsignals as visible traces on a plurality of lines, one alongside theother in succession, each of said lines having a value corresponding toits position with respect to the other of said lines, c. means forreading out of said storagE means all of said signals concurrently witheach of said lines, and d. display control means responsive to the sumof the value to which each said signal read out of said storage meanscorresponds and the value corresponding to the position of each linewith respect to the other of said lines on said display means foroperating said display means to provide a visible trace during read outof each said signal when said sum equals a certain value whereby toprovide a sequence of visible traces on said display means whichprovides said graphic display which represents said parameter.
 2. Theinvention as set forth in claim 1 wherein said display means comprisesmeans providing a TV display wherein each of said lines is a succesivehorizontal line of said display, and means for controlling the intensityof said lines to provide said traces.
 3. The invention as set forth inclaim 2 wherein said storage means comprises a recirculating, pluralstage digital memory, and said readout means comprises means for readingout digital signals presented in a stage in said memory, each during asuccessive portion of each of said horizontal lines.
 4. The invention asset forth in claim 3 wherein said display control means comprises meansfor generating digital controls signals concurrently with the generationof each of said horizontal lines, each of which digital control signalsrepresents the relative position of the horizontal line for which it isconcurrently generated, and means for providing a signal to saidintensity control means for rendering said line visible when the sum ofthe values represented by said digital control signal and said digitalsignal exceeds a certain value.
 5. The invention as set forth in claim 4including means for changing the location of said digital signals insaid stages of said recirculating digital memory for horizontally movingthe position of said graphic display of said parameter.
 6. The inventionas set forth in claim 4 including means for changing the values of saiddigital control signals for vertically moving the position of saidgraphic display of said parameter.
 7. The invention as set forth inclaim 4 which comprises a control recirculating plural stage digitalmemory for storing control digital signals in successive stages thereof,means for successively reading out digital signals from said controlmemory in synchronism with the digital signals from said first namedmemory, and means for controlling said means for providing said signalto said intensity control means in accordance with the value of saidread-out control digital signals.
 8. The invention as set forth in claim4 wherein a plurality of said recirculating memories are provided eachhaving storage for a different parameter, and wherein means are includedin said intensity control means responsive to digital signals fromdifferent ones of said memories for providing the graphic displays whichrepresents different parameters vertically offset from each other. 9.The invention as set forth in claim 4 wherein a plurality of saidrecirculating memories are provided, and wherein means are included insaid intensity control means separately responsive to digital signalsfrom different ones of said memories for providing said visible traceswith different intensity whereby to simultaneously provide a pluralityof said graphic displays each consisting of traces having a certaindistinct intensity.
 10. The invention as set forth in claim 4 furthercomprising an analog to digital converter for providing said digitalsignals for storage in said memory, and means operative once during eachrepetitive display of said parameter for reading a digital signal fromsaid converter into said memory.
 11. A speech training system whichcomprises a. means for providing signals representing a parameter ofvoiced speech, b. recirculating memory means for storing said signalswhich are voiced during a period of time, c. display means for providinga Trace representing the signals stored in said memory, d. timing meansfor circulating said signals in said memory in timed relationship withthe read out of signals into said display means, and e. control meansoperated by said timing means for controlling said memory means and saidsignals which are read out of said memory means for varying the locationof said trace.
 12. The invention as set forth in claim 11 furthercomprising a plurality of said memories, a plurality of said means forproviding said signals at least one from the voice of a trainee andanother from the voice of a therapist, means for storing said traineesignals and said therapist signals in different ones of said memories,and means for operating said display means for providing a plurality ofsaid traces of each of the signals from a different one of saidmemories.
 13. The invention as set forth in claim 12, including displaycontrol means for moving said plurality of traces with respect to eachother so that they can be overlaid for comparison purposes.
 14. Theinvention as set forth in claim 12 wherein said signals providing meansincludes means for providing a plurality of signals from the voice ofsaid trainee and a plurality of signals from the voice of said therapisteach representing a plurality of speech parameters, means for storingeach of said signals in a separate one of said plurality of memories,and means included in said display operating means for providing aplurality of separate traces each corresponding to the signals stored ina different one of said memories.
 15. The invention as set forth inclaim 14 further comprising means responsive to each of said speechsignals for providing signals representing the certain characteristicsof said speech, a recirculation control memory for storing said signals,and means included in said display control means responsive to saidsignals stored in said control memory for changing the size of saidtraces representing said characteristics.
 16. The invention as set forthin claim 11 wherein said display means comprises a screen means forscanning a raster of successive, vertically displaced horizontal linesacross said screen and means for controlling the intensity of saidlines, said recirculating memory comprises register means for storingdigital signals corresponding to successive values of said parameter,means for providing digital signals corresponding to the verticalposition of each of said horizontal lines, means for reading out saidmemory during the scanning of each of said horizontal lines and meansfor operating said intensity control means to provide a trace on saidscreen when the sum of said vertical position signal and said parametervalue signal exceeds a predetermined value.
 17. The invention as setforth in claim 16 including control means for changing said traceincluding means operative to generate digital control signals, and meansfor combining said digital control signals and said sum operative tochange said sum.